1. Field of the Invention
The present invention relates to a card reader writer for transmitting and receiving information to and from magnetic and IC cards.
2. Description of the Related Art
Automatic monetary machines such as the cash dispenser (CD) and the automatic teller machine (ATM) which use magnetic and IC cards as their information recording media have been developed to save and speed up business works at the front of financial agencies such as the bank, post office and credit bank.
These automatic monetary machines need no person attended or in charge. Therefore, they have been improved day by day to need no maintenance and enhance their reliability so as to allow any customer to use them with a sense of relief even on holiday. Particularly when the card reader-writer is jammed by the card on holiday, the situation becomes critical because the card cannot be returned to the customer. In order to avoid this, therefore, the card reader-writer is provided with various measures.
The conventional card reader-witer has a card inserting opening in the center of one side of its frame and the card is selectively inserted into this card inserting opening. Magnetic stripes are formed on the top and underside of the card. Take-in rollers for taking the card inserted into the card inserting opening into the card reader-writer are arranged one upon the other in the frame and adjacent to the card inserting opening.
On the other hand, a group of paired carrying rollers is arranged behind the take-in rollers in the frame in such a way that the paired carrying rollers are opposed to each other in the vertical direction. Each of these carrying and take-in rollers is made of rubber or plastics. Further, magnetic heads are located adjacent to the carrying rollers, opposing to each other in the vertical direction with a certain magnetic gap interposed between them. The carrying and take-in rollers are driven commonly by a motor.
The card inserted into the card inserting opening is taken into the card reader-writer by the take-in rollers and carried backward between the front paired carrying rollers. This card is carried backward by pressing force created between the carrying rollers by springs and by friction created by the carrying rollers rotated. In this case, the card is carried to the area paired carrying rollers while spreading the upper and lower magnetic heads. When the card passes between the magnetic heads in this manner, the magnetic heads read information recorded on the magnetic stripe on the card and write information on the magnetic stripe thereon. When a series of these processes is finished, the card is returned to the card inserting opening and then back to the customer.
In the case of the conventional card reader-writer arranged as described above, however, the card is frictionally carried using frictional force between the rubber- or plastics-made take-in rollers and between the rubber- or plastics-made carrying rollers and the card. Therefore, the frictional force changes depending upon the surface state of each of the rollers, that of the card and material of which the card is made. In addition, each of the rollers repeats its elastic deformation every time the card is carried between the rollers. As the result, the card carrying velocity cannot be kept certain, thereby preventing reading and writing of magnetic information from being accurately achieved.
Further, the card is successively carried backward by three pairs of the carrying rollers and every time it is taken between the paired carrying rollers, it is impacted by the rollers and thus vibrated. The stability of carrying the card is thus lowered, thereby making it impossible to accurately read and write the magnetic information.
Furthermore, when the carrying rollers are used for a long time without adding any maintenance to them, dust, oil and the others adhere to their surface to thereby lower their card carrying capacity. In the worst case, they cannot carry the card.
In the case of the IC-incororated card, the magnetic stripe, the embossed portion and the IC node portion are arranged adjacent to one another on the card in the width direction thereof. This allows the card to be sandwiched between the carrying rollers only at such an area of the card that extends about 2-3 mm from one side edge of the card in the width direction thereof. It is therefore feared that the card carrying capacity of the carrying rollers is further lowered.
As described above, the conventional card reader-writer uses the system of carrying the card by the frictional force created between the rubber-made rollers and the card. This makes it difficult to carry the card at a certain velocity. As the result, reliable reading and writing of information cannot be attained.